<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>

<body>
    <form action="" method="post">
        <h1>计算器</h1>
        数字1：<input type="text" name="num1"><br>
        数字2：<input type="text" name="num2"><br>
        <input type="submit" value="点击相加">
    </form>
</body>

</html>